A single rack ran outside the narrow gauge tracks and was engaged by a large cog wheel on the left side of the locomotive.

The piston crossheads slid in guides, rather than being controlled by a parallel motion linkage like the majority of early locomotives.

According to George Stephenson, giving evidence to a committee of Parliament, the driver had tampered with the boiler's safety valve.

[5] Salamanca is probably the locomotive referred to in the September 1814 edition of Annals of Philosophy: "Some time ago a steam-engine was mounted upon wheels at Leeds, and made to move along a rail road by means of a rack wheel, dragging after it a number of waggons loaded with coals."

[6] A model of the locomotive, built by Murray in 1811, is part of the collection held at Leeds Industrial Museum.